1. Field of the invention
The present invention generally relates to energy sensing devices and, more particularly, to an arrangement for detecting energy from an energy radiating source, for use in controlling the attitude of a vehicle, containing the arrangement, with respect to the energy radiating source.
2. Description of the Prior Art
On-course navigation of a space vehicle, such as a space communication satellite or a spacecraft, flying interplanetary missions, depends upon proper orientation of the vehicle on its various axes. The sun is often used as a reference for pitch or yaw axis attitude control. Briefly, the direction of the light from the sun is sensed by light sensors, often referred to as sun sensors, which cause the actuation of attitude control gas jets to achieve and maintain proper vehicle orientation with respect to the sun. In the early stages of space exploration, spacecrafts included a sun sensor system which included sun acquisition sensors or detectors and a sun gate decoder, in order to assure acquisition of the sun direction from any arbitrary vehicle orientation. The cost of fabrication of such sensors is quite high. Furthermore, the sensors must be reconfigured for each new spacecraft design and the circuitry has to be modified for different solar intensities. The elimination of the need for the expensive sun acquisition sensors and the sun gate detector is highly desirable from a cost reduction point of view. Also the elimination of the various sensors would reduce the overall weight of the sun sensor system.